Vane for rotary fluid machine

ABSTRACT

A vane for a vane-type rotary air motor having an increased thickness or projecting abutments located along its inner edge to prevent it from seating flatly and in intimate contact with the wall of its slot to avoid any adherence or sticking of the vane against the slot wall that would interfere with the sliding movement of the vane during the operation of the air motor.

United States Patent 1191 Kramer et a1.

1451 Oct. 23, 1973 VANE FOR ROTARY FLUID MACHINE [73] Assignee: Ingersoll-Rand Corporation, New

York, NY.

[22] Filed: Sept. 8, 1971 [21] Appl. No.: 178,622

2,371,081 3/1945 Tucker et al. 418/268 3,076,415 2/1963 Farron 418/268 FOREIGN PATENTS OR APPLICATIONS 958,712 5/1964 Great Britain 418/268 842,451 6/1952 Germany 418/138 Primary ExaminerCarlton R. Croyle Assistant Examiner-John J. Vrablik Att0rneyFrank S. Troidl et al.

[57] ABSTRACT A vane for a vane-type rotary air motor having an increased thickness or projecting abutments located along its inner edge to prevent it from seating flatly and in intimate contact with the wall of its slot to avoid any adherence or sticking of the vane against the slot. wall that would interfere with the sliding movement of the vane during the operation of the air motor.

9 Claims, 5 Drawing Figures 52 US. Cl. 418/259, 418/270 51] Int. c1...... F016 21/00, F03C 3 00, F04C 29 00 [58] Field of Search 418/241, 138,270, 418/268, 234, 235, 266-269, 236, 238, 259

[56] References Cited UNITED STATES PATENTS 2,499,763 3 1950 Livermore 418/268 2,273,131 3 1942 Livermore 418/268 867,172 9 1907 Troup 418/266 2,324,903 7 1943 Beckman 418/269 3,171,587 3/1965 Schaller et al. 418/124 PATENIEI] URI 2 3 I973 INVENTORS LEO KRAMER HAROLD E. HARRIS, JR.

ATTORNEY VANE FOR ROTARY FLUID MACHINE BACKGROUND OF THE INVENTION This invention relates in general to the art of rotary machines and more particularly to rotary fluid machines of the type having rotors carrying slotted vanes.

Heretofore, it has been conventional to make vanetype air motors with rotors having several vane slots extending generally radially, longitudinally and spaced angularly about the rotor axis. These vane slots are normally kerfs cut in the rotor having an even thickness throughouttheir extent and the vanes sliding in the slots are also of a uniform thickness, being normally cut from a large sheet or plate-like member of a uniform thickness. The flat faces on both the vanes and slot walls allow the vanes to seat flatly and in intimate engagement against a slot wall. We have found that this flat or intimate engagement between a vane and its slot wall tends to cause the vane to stick against the wall and retard its freedom to slide easily during the operation of a vane motor, particularly when a film of oil exists between the vane andits slot walls. It is normal for oil to be present in an air motor since it is customary to lubricate such motors by feeding small amounts of oil into the air supply of such motors. This sticking of the vanes contributes to the erratic performanceot' conventional air motors at low speeds when the centrifugal forces acting on the vanes is minimal.

SUMMARY OF THE INVENTION The principal object of this invention is to substantially eliminate or minimize the tendency of the vanes of a rotary fluid machine to stick against the wall of their slots.

Other important objects of this invention are: to improve the performance of vane-type air motors; and to provide an improved vane for use in rotary fluid machines, including motors, compressors, and pumps.

In general, the objects of this invention are attained by providing either the vane or the vane slot with a means on its inner face to slightly tilt or cant the vane relatively to its slot wall and thus prevent the vane from lying or seating flat against the slot wall. This purpose can be accomplished by mounting a series of buttons or abutments on each face of the vane near its inner edge, forming the vane with a T-shaped cross section with the larger thickness located near or along its inner edge, or providing the slot with a cross section that will prevent the vane from seating flat on the vane slot wall.

BRIEF DESCRIPTION OF DRAWINGS The invention is described in connection with the drawings wherein:

FIG. 1 is across section taken transverse to the axis of a vane-type rotary motor incorporating an embodiment of the invention;

FIG. 2'is an enlarged fragmentary view of a portion of FIG. 1 illustrating a vane;

FIG. 3 is an elevational view of the vane of FIG. 2 looking at one of its faces;

FIG. 4 is a section similar to FIG. 2 but on a smaller scale showing a second embodiment of the invention; and

FIG. 5 is a section similar to FIG. 4 of a third embodiment.

DESCRIPTION OF PREFERRED EMBODIMENT The air motor 1 shown in FIG. 1 includes a cylinder 2 and a rotor 3 rotatably and eccentrically mounted within the cylinder 2 with a fluid chamber 4 formed by and located between the cylinder 2 and rotor 3. The rotor 3 is supported on bearings (not shown) carried by end plates (not shown) closing the opposite ends of the cylinder 2 to form the chamber 4. The rotor 3 contains a series of angularly spaced slots 6 extending radially and longitudinally of the rotor. Each slot 6 is formed like a kerf cut in the rotor, is of uniform thickness throughout its extent, and is defined or bounded by a pair of parallel spaced and flat sides or walls 7 and a bottom 8 in the rotor 3. As shown in FIG. 1 the cylinder includes a pair of fluid ports 9 and 10 for supplying and exhausting fluid from the motor chamber 4 and a primary exhaust port 11. All of the foregoing structure is conventional in the pneumatic or air motor art, and therefore is not described in further detail.

A vane 14 is slidably mounted in each of the slots 6 for moving radially in the slot in a manner that is also conventional in the art of vane-type rotary machines. The vane 14 generally has a sheet or plate-like form and includes an outer edge 15 which may be rounded for engaging the cylinder 2, an inner edge 16 spaced opposite to the outer edge and a pair of longitudinally spaced end edges 17. The inner corners 18 of the vane between the inner edge 16 and the end edges 17 are cut away to form bevelled corners which are conventional in fluid motor vanes.

As can be seen in FIG. 2, the vane 14 has a T-shaped cross section, being composed of a stem portion 20 and a bar portion 21. The stem portion 20 is of a uniform thickness and a pair of faces 22 that are flat and extend over most of the area of the vane. The bar portion 21 is thicker than the stem portion 20 and projects beyond both of the faces 22 along the inside edge 16 of the vane. The projection of the bar portion 21 beyond the flat faces 22 of the stem portion 20 results in .the vane 14 being tilted or canted in the vane slot 6 during the operation of the motor, as illustrated in FIG. 2. Tilting the vane 14 prevents it from seating flat against the slot wall 7 and thereby prevents it from becoming stuck, glued, or adhered against the wall by means such as an oil film between the vane 14 and the slot wall 7. The bevelled corners 18 of the vane 14 allow any fluid that might otherwise be trapped between the vane and the slot wall 7 to escape freely to the bottom 8 of 'the slot 6, although we have found that satisfactory'vanes can be made without the bevelled corners 18 extending entirely through the bar portion 21 into the stem-portion 20. The line of contact between the flat face 22 of the stem portion of the vane 14 and the outer edge 24 of the slot wall 7 as shown in FIG. 2 provides a seal between the vane and the slot to prevent undue leakage therebetween. It will be understood by those knowledgeable in the art of air motors that during the opera-' tion of an air motor or any other vane-type machine, the differential of pressure across the vane 14 will normally urge the vane against one of the slot walls 7 and the particular wall 7 that the vane is seated against may alternate from wall to wall at different places in the ro-. tary path of the vane around the motor chamber.

SECOND EMBODIMENT FIG. 4

The embodiment shown in FIG. 4 includes a vane 28 that accomplishes the same purpose as in the first embodiment by having a series of abutments or button heads 29, which may be the opposite heads of a rivet mounted along the inner edge 30 of the vane 28.

THIRD EMBODIMENT FIG.

The third embodiment includes a rotor 3 containing a vane 34 of uniform thickness sliding in a vane slot 35 having a T-shaped cross section. The outer portion 36 of the slot 35 has a wide thickness and the inner portion 37 is centrally located and of a smaller thickness providing each side wall of the slot 35 with a step 38. As the vane 34 moves radially during operation, it may be supported on alternate sides of the slot 35, depending on the relationship of the forces acting on the vane and throughout its movement. The combination of the step 38 and the outer corner 39 will prevent the vane 34 from lying in face-to-face contact with the sides of the slot 35. Although the slot 35 could have other crosssectional shapes to provide the step 38 for the vane 34 to ride on, the T-shape is desirable because it can be easily formed using a stepped milling cutter traveling the length of the rotor 3.

While several embodiments of the invention are shown and described in detail, this invention is not limited simply to the specifically described embodiments, but contemplates other embodiments and variations utilizing the concepts and teachings of this invention.

We claim:

1. A vane for use in a slotted rotor of a rotary fluid machine requiring substantial relative movement between said vane and said rotor, said vane comprising: sheet-like vane member having an outer edge adapted to engage the inside of a machine cylinder, a pair of longitudinally spaced end edges and an inner edge spaced oppositely from said outer edge;

said vane member having a pair of faces which are generally flatover most of the facial area of said member; and

means provided on each of said faces near said inner edge projecting outwardly from said face for a short distance beyond the remainder of said face to prevent the face from seating flatly against a flat wall of a vane slot.

2. The vane of claim 1 whereby:

said vane member has a T-shaped cross section with its greater thickness located near its inner edge.

3. The vane of claim 1 whereby:

said means include a series of abutments fixed on said face of the vane member adjacent and along its inner edge.

4. In a vane-type rotary fluid machine, the combina- 4 tion comprising:

a rotor mounted eccentrically in a machine cylinder and containing a vane slot in the periphery of the rotor extending longitudinally and generally outwardly of the rotor axis, said slot including a pair of spaced side walls,

sheet-like vane sliding in said rotor slot and having an outer edge adapted to engage the inside of the machine cylinder, a pair of longitudinally spaced end edges, an inner edge spaced oppositely from said outer edge, and a pair of side walls,

said rotor, cylinder and vane cooperate so that the vane continuously moves between a position wherein the vane is extended a substantial distance beyond the periphery of the rotor and a position wherein the vane is substantially retracted within the periphery of the rotor; and

means on each side wall of one of said pair of side walls for supporting the vane at a pair of points spaced generally along the slot in a direction at right angles to the axis of the rotor during the operation of the machine thereby preventing the vane from seating against the side walls of the vane slot in intimate face-to-face engagement over a major portion of the area of the vane side walls housed in the vane slot.

5. The combination of claim 1, wherein:

the side walls of the vane slot carry steps spaced inwardly from the rotor periphery and adapted to support a vane in spaced relationship from the remainder of the vane slot side walls during the operation of the machine.

6. The combination of claim 5 wherein:

said vane slot has a T-shaped cross section with the wider portion of the slot being located adjacent the periphery of the rotor.

7. The combination of claim 1 wherein:

said means is provided on each of the side walls of said vane near said inner edge projecting outwardly from each vane side wall for a short distance beyond the remainder of the side wall to prevent the vane side wall from seating flatly against a side wall of the vane slot.

8. The vane of claim 7 whereby:

said vane has a T-shaped cross section with its greater thickness located near its inner edge.

9. The vane of claim 7 whereby:

said vane includes a series of abutments fixed on each of said side wall of the vane adjacent and along its inner edge. 

1. A vane for use in a slotted rotor of a rotary fluid machine requiring substantial relative movement between said vane and said rotor, said vane comprising: sheet-like vane member having an outer edge adapted to engage the inside of a machine cylinder, a pair of longitudinally spaced end edges and an inner edge spaced oppositely from said outer edge; said vane member having a pair of faces which are generally flat over most of the facial area of said member; and means provided on each of said faces near said inner edge projecting outwardly from said face for a short distance beyond the remainder of said face to prevent the face from seating flatly against a flat wall of a vane slot.
 2. The vane of claim 1 whereby: said vane member has a T-shaped cross section with its greater thickness located near its inner edge.
 3. The vane of claim 1 whereby: said means include a series of abutments fixed on said face of the vane member adjacent and along its inner edge.
 4. In a vane-type rotary fluid machine, the combination comprising: a rotor mounted eccentrically in a machine cylinder and containing a vane slot in the periphery of the rotor extending longitudinally and generally outwardly of the rotor axis, said slot including a pair of spaced side walls; a sheet-like vane sliding in said rotor slot and having an outer edge adapted to engage the inside of the machine cylinder, a pair of longitudinally spaced end edges, an inner edge spaced oppositely from said outer edge, and a pair of side walls, said rotor, cylinder and vane cooperate so that the vane continuously moves between a position wherein the vane is extended a substantial distance beyond the periphery of the rotor and a position wherein the vane is substantially retracted within the periphery of the rotor; and means on each side wall of one of said pair of side walls for supporting the vane at a pair of points spaced generally along the slot in a direction at right angles to the axis of the rotor during the operation of the machine thereby preventing the vane from seating against the side walls of the vane slot in intimate face-to-face engagement over a major portion of the area of the vane side walls housed in the vane slot.
 5. The combination of claim 1, wherein: the side walls of the vane slot carry steps spaced inwardly from the rotor periphery and adapted to support a vane in spaced relationship from the remainder of the vane slot side walls during the operation of the machine.
 6. The combination of claim 5 wherein: said vane slot has a T-shaped cross section with the wider portion of the slot being located adjacent the periphery of the rotor.
 7. The combination of claim 1 wherein: said means is provided on each of the side walls of said vane near said inner edge projecting outwardly from each vane side wall for a short distance beyonD the remainder of the side wall to prevent the vane side wall from seating flatly against a side wall of the vane slot.
 8. The vane of claim 7 whereby: said vane has a T-shaped cross section with its greater thickness located near its inner edge.
 9. The vane of claim 7 whereby: said vane includes a series of abutments fixed on each of said side wall of the vane adjacent and along its inner edge. 